After _header_strip the header contains only non-printable, it returns None, and None can't split.
https://github.com/openstack/swift3/blob/1.12/swift3/request.py#L280
After _header_strip the header contains only non-printable, it returns None, and None can't split.
https:/ /github. com/openstack/ swift3/ blob/1. 12/swift3/ request. py#L280